DE102021003351A1 - Vacuum processing system with a process chamber with a vacuum control valve - Google Patents

Abstract

Vacuum processing system (1) having a vacuum chamber (10) and a vacuum control valve (20). The vacuum valve (20) has a first valve seat (21a), which has a first valve opening (22a) defining a first opening axis (O) and a first sealing surface surrounding the first valve opening (O), and a first valve disk (23a) with a to the first sealing surface corresponding first contact surface. The vacuum processing system also has a drive unit (30) which is designed and coupled to the first valve disk (23a) in such a way that it can be moved at least from an open position to a closed position and back. The first valve seat (21a) is arranged inside the vacuum chamber (10) and divides the vacuum chamber (10) into a main process chamber (11) for processing the substrate and a sub-process chamber (12). The first sealing surface extends orthogonally to the first opening axis (O) and points in the direction of the auxiliary process chamber (12). The first valve disk (23a) is adjustably arranged in the secondary process chamber (12).

Description

The invention relates to a vacuum system with a vacuum valve with a plurality of valve disks and a corresponding plurality of valve part openings.

In general, vacuum valves for controlling a volume or mass flow and for essentially gas-tight closing of a flow path, which leads through an opening formed in a valve housing, are known in various embodiments from the prior art and are used in particular in vacuum chamber systems in the field of IC, semiconductors - or substrate fabrication, which must take place in a protected atmosphere with as few contaminating particles as possible.

Such vacuum chamber systems include, in particular, at least one evacuatable vacuum or process chamber provided for receiving semiconductor elements or substrates to be processed or produced, which has at least one vacuum chamber opening through which the semiconductor elements or other substrates can be guided into and out of the vacuum chamber, and at least one vacuum pump to evacuate the vacuum chamber. For example, in a production facility for semiconductor wafers or liquid crystal substrates, the highly sensitive semiconductor or liquid crystal elements sequentially pass through a number of process vacuum chambers in which the parts located within the process vacuum chambers are each processed using a processing device. The highly sensitive semiconductor elements or substrates must always be in a protected atmosphere - especially in an airless environment - both during the processing process within the process vacuum chambers and during transport from chamber to chamber.

For this purpose, on the one hand, peripheral valves are used to open and close a gas inlet or outlet and, on the other hand, transfer valves are used to open and close the transfer openings of the vacuum chambers for inserting and removing the parts.

The vacuum valves through which semiconductor parts pass are referred to as vacuum transfer valves due to the area of application described and the associated dimensioning.

Peripheral valves, on the other hand, are used in particular to control or regulate the gas flow between a vacuum chamber and a vacuum pump or another vacuum chamber. Peripheral valves are located, for example, within a pipe system between a process vacuum chamber or a transfer chamber and a vacuum pump, the atmosphere or another process vacuum chamber. The opening cross section of such valves, also known as pump valves, is generally smaller than that of a vacuum transfer valve. Since peripheral valves, depending on the area of application, are not only used to completely open and close an opening, but also to control or regulate a flow rate by continuously adjusting the opening cross section between a completely open position and a gas-tight closed position, they are also referred to as control valves. A possible peripheral valve for controlling or regulating the gas flow is the pendulum valve.

In a typical pendulum valve, as is known, for example, from US Pat. No. 6,089,537 (Olmsted), in a first step a generally round valve disk is pivoted in a rotary manner via a generally also round opening from a position releasing the opening into an intermediate position covering the opening. In the case of a slide valve, as described, for example, in US Pat. No. 6,416,037 (Geiser) or US Pat pushed the opening overlapping intermediate position. In this intermediate position, the valve disk of the pendulum or slide valve is located at a distance opposite the valve seat surrounding the opening. In a second step, the distance between the valve disk and the valve seat is reduced, so that the valve disk and the valve seat are evenly pressed against one another and the opening is closed in a substantially gas-tight manner. This second movement is preferably substantially in a direction perpendicular to the valve seat. The seal can be made, for example, either by a sealing ring on the closing side of the valve disk, which is pressed onto the valve seat surrounding the opening, or by a sealing ring on the valve seat, against which the closing side of the valve disk is pressed. Due to the two-step closing process, the sealing ring between the valve disk and the valve seat is hardly subjected to shearing forces that would destroy the sealing ring, since the movement of the valve disk in the second step takes place essentially in a straight line perpendicular to the valve seat.

Different sealing devices are known from the prior art, for example from U.S. 6,629,682 B2 (Duel). A suitable material for sealing rings and seals in vacuum valves is, for example, fluororubber, also known as FKM, in particular the fluoroelastomer known under the trade name "Viton", and perfluororubber, FFKM for short.

The multi-stage movement described, in which the closure member is first pushed across the opening without the seal coming into contact with the valve seat, and the closure member is then pressed essentially perpendicularly onto the valve seat, offers the advantage that the seal is pressed almost exclusively vertically, without the seal being subject to lateral or longitudinal stress (avoidance of particles), also the possibility of regulating the flow of a medium (e.g. process gas) through the valve opening.

Since the valves mentioned above are used, among other things, in the production of highly sensitive semiconductor elements, the generation of particles caused in particular by the actuation of the valve and the mechanical load on the valve closure element and the number of free particles in the valve chamber must - as already mentioned - be kept as low as possible. Particle generation is primarily a consequence of friction, for example through metal-to-metal contact or through abrasion.

As described above, vacuum control valves are used to set a defined process environment in a process chamber. The control is typically carried out here using a pressure signal, which provides information about the internal chamber pressure, and using a target variable, i.e. a target pressure, which is to be achieved by means of the control. The position of a valve closure (valve plate) is then varied as part of the control in such a way that the target pressure is reached within a certain period of time.

The time required for adjustment depends directly on the size of the volume of the process chamber to be evacuated. A comparatively large chamber can therefore be disadvantageous, especially when processing small substrates, i.e. a large dead volume should be avoided accordingly.

What the above embodiments have in common is that, in particular in the case of regulation, a control curve (volume flow over time unit) resulting from one of these constructions typically occurs with a disadvantageous curve shape. In particular, in the transition from an almost closed valve state to a completely closed valve state, the curve shows a clearly inhomogeneous course due to a “snapping effect” that occurs in the process. A flow through the opening is thereby abruptly interrupted. Fine control at very low pressures is therefore very difficult or impossible to implement.

Another critical factor associated with semiconductor manufacturing is the use and handling of process gas required for individual processing steps. The control valve typically also assumes the function of providing a defined gas concentration, i.e. regulating it by means of a variable gas outflow through the valve. The process gas is usually fed in on a side of the process chamber opposite the evacuation opening.

In addition to the gas concentration and the atmospheric pressure, a distribution of the process gas that is as homogeneous as possible is also advantageous, at least in the region of the substrate to be processed. A flow of the gas through the process chamber that is as symmetrical as possible, that is to say both when the gas is added and when it is evacuated, can be helpful for this.

the U.S. 6,994,311 B2 discloses a vacuum control valve with the aim of establishing a symmetrical flow through an orifice in an open valve position. The valve disk is suspended centrally on a guide (valve rod) and can be guided axially so that a volume flow through the opening can be adjusted depending on the distance between the valve disk and the valve seat. A disadvantage of this solution, however, is that there must be a mechanical connection to the center of the valve opening in order to provide guidance for the valve disk. This mechanical connection breaks up the symmetry of the flow, at least in part, and leads to turbulence at the connecting elements.

The invention is therefore based on the object of providing a vacuum control valve or vacuum processing system which on the one hand provides precise control or adjustment of the valve opening and thus a flow through the opening and on the other hand a homogeneous fluid distribution in a process chamber.

In particular, it is the object of the invention to provide the above improvements with comparatively short adjustment times of the valve closure.

Another task is to provide an editing system that the precise rules ment of a fluid flow and a comparatively small process volume.

These objects are solved by realizing the features of the independent claims. Features that further develop the invention in an alternative or advantageous manner can be found in the dependent patent claims.

The invention relates to a construction of a vacuum processing system which has at least one vacuum chamber or process chamber and a vacuum valve, in particular a vacuum control valve. The vacuum valve provides improved flow and drainage of process fluid from a process volume in terms of flow behavior homogeneity. At the same time, an adjustment time for a change from an open state to a closed state (or vice versa) can be significantly improved, i.e. reduced. Due to the structure according to the invention, the vacuum chamber is divided into a main chamber and a secondary chamber by means of the valve, with the valve being arranged inside the vacuum chamber.

The advantages and improvements mentioned are provided in particular by dividing a hitherto single valve opening known in the prior art into a plurality of partial valve openings of the vacuum valve. The partial openings are preferably arranged symmetrically around a central valve axis. Each valve part opening is provided by a valve seat and surrounded by a sealing surface. The sum of the areas of the multiple valve part openings gives the area of the total valve opening.

The total valve opening cross-section results from the sum of the opening cross-sections of the several valve part openings, with the opening cross-section depending on the respective opening state of the valve part openings, i.e. on the flow area released by the respective valve closure.

In particular, the valve seats form a lower boundary of the main process chamber and an upper boundary of the secondary process chamber. A seal for producing a gas-tight closure of the main process chamber is preferably provided on the underside of the valve seats, ie not in the main process chamber but in the secondary process chamber. Correspondingly, the valve plates for closing the openings are located in the secondary process chamber and can be moved in this chamber along an adjustment axis. Alternatively or additionally, the seal can be provided on the valve disk side.

Due to the fact that the valve plates together with the drive components are arranged in or on the secondary process chamber, a fluid flow into or through the main chamber is not influenced by the valve. As a result, an improved symmetrical (through) flow and thus improved substrate processing can take place in the main process chamber.

The valve seats are preferably arranged around the central chuck in such a way that fluid can flow around the chuck with a homogeneous flow distribution.

The invention thus relates to a vacuum processing system for processing, in particular by means of deposition (ALD, atomic layer deposition/epitaxy) or etching (ALE, atomic layer etching), of a substrate or workpiece, in particular of a semiconductor.

The vacuum processing system has a vacuum chamber that defines an evacuable interior volume for creating a vacuum and for processing the substrate in the interior volume. In addition, the vacuum processing system has a vacuum control valve for controlling a volume or mass flow of a fluid flowing through the vacuum chamber and for interrupting a flow path of the fluid in a gas-tight manner.

The vacuum control valve has at least one first valve seat, which has a first valve opening defining a first opening axis and a first sealing surface surrounding the first valve opening, and at least one first valve disk with a first contact surface corresponding to the first sealing surface.

The vacuum processing system has at least one drive unit which is designed and coupled to the first valve disk in such a way that this valve disk can be adjusted (e.g. motorized) at least from an open position to a closed position and back. In the open position, the first valve disk and the first valve seat are present without contact relative to one another. In the closed position, there is a sealing contact between the first sealing surface and the first contact surface via an intermediate sealing element, with the first valve opening being closed in a gas-tight manner as a result.

According to the invention, the first valve seat is arranged within the vacuum chamber and divides the vacuum chamber into a main process chamber for processing the substrate and a secondary process chamber. The first sealing surface extends orthogonally to the first opening axis and points in the direction of the secondary process chamber, in particular parallel to the first opening axis. The first valve plate is adjustably arranged in the secondary process chamber.

In one embodiment, the vacuum control valve can have a second valve seat, which has a second valve opening defining a second opening axis and a second sealing surface surrounding the second valve opening, and a second valve disk with a second contact surface corresponding to the second sealing surface. The second valve seat can be arranged inside the vacuum chamber and together with the first valve seat divide the vacuum chamber into the main process chamber and the sub-process chamber. The second sealing surface extends orthogonally to the second opening axis and points in the direction of the secondary process chamber, in particular parallel to the second opening axis. The second valve disk can be arranged adjustably in the secondary process chamber.

As a result, a total valve opening of the vacuum control valve can be formed at least by the first valve opening as the first partial valve opening and the second valve opening as the second partial valve opening.

The provision of at least two groups, each comprising at least one valve seat and one valve closure (valve plate), allows a symmetrical arrangement around a center of the vacuum valve. This allows on the one hand a symmetrical volume flow through the valve and on the other hand a comparatively quick actuation (i.e. quick adjustment of the valve closures due to the comparatively small individual masses of the valve closures) with the possibility of a very flexible volume flow control, i.e. also the achievement of a comparatively large total opening cross-section from a closed position (and vice versa) in a short time.

In one embodiment, the vacuum processing system can have a third valve seat, which has a third valve opening defining a third opening axis and a third sealing surface surrounding the third valve opening. Accordingly, a third valve disk can be provided with a third contact surface that corresponds to the third sealing surface.

The third valve seat can be arranged inside the vacuum chamber and together with the first and second valve seats divide the vacuum chamber into the main process chamber and the sub-process chamber. The third sealing surface can extend orthogonally to the third opening axis and point in the direction of the auxiliary process chamber, in particular parallel to the third opening axis. The third valve disk can be adjustably arranged in the secondary process chamber.

In this case, the overall valve opening can additionally be formed by the third valve opening as the third partial valve opening.

By arranging a third combination or further combinations of valve seat and valve disk, the symmetry of the entire valve opening around a central axis of the valve can be maintained or increased and the symmetry of the volume flow (concentric) through the valve can thus be further improved.

In particular, the drive unit can be coupled to the second or third valve disk in such a way that the coupled valve disks move at least from a respective open position, in which the respective valve disk and the respective valve seat are in contact without contact relative to one another, to a closed position, in which via a respective intermediate sealing element there is an axially sealing contact between the respective sealing surface and the respective contact surface and the respective valve part opening is closed in a gas-tight manner as a result, and can be adjusted back.

The drive unit can be designed, for example, as an actuator or electric motor, in particular a linear motor or stepping motor.

In one embodiment, the vacuum control valve can have a coupling arrangement, which coupling arrangement provides a mechanical coupling of the first valve disk to the second valve disk, and in particular to the third valve disk, and is connected to the drive unit in such a way that the respective valve disks can be adjusted together by means of the drive unit . The coupling arrangement can be implemented, for example, with a shaft, joints (e.g. cardan joints), bearings and/or transmissions.

For example, a mechanical solution can be used to simultaneously adjust several or all of the coupled valve disks. In this way, a homogeneous and symmetrical fluid flow through the valve can be achieved in particular by the fact that the same opening cross section is provided for all openings when the valve part opening is opened for the first time and the flow through all openings is the same in terms of volume or mass flow and remains the same as a result.

According to a further embodiment, the drive unit can have at least a first and a second, in particular a third, drive component, in particular respective motors senior The first drive component can be coupled to the first valve disk and the second drive component to the second valve disk, in particular the third drive component can be coupled to the third valve disk.

In contrast to the previous version, each of the valve disks can be controlled and adjusted individually in this variant. This allows greater flexibility in terms of adjusting the flow behavior through the valve and in particular through the main process chamber. In this way, for example, asymmetries in the volume flow can be compensated for, which are caused by the processing devices present in the process chamber or by an asymmetrical arrangement of fluid inlets. Such a compensation can be implemented by providing different opening cross sections for the individual valve part openings.

In particular, the flow behavior within the chamber can be adjusted in such a way that an asymmetrical flow, which is caused, for example, by a device in the chamber for processing a substrate, can be compensated for. When using a conventional valve, the flow would take place correspondingly inhomogeneously through the process chamber. Due to the adjustability of the outflow behavior by means of the valve according to the invention, the outflow of the fluid can counteract the asymmetrical flow through the chamber and ultimately result in an overall symmetrical flow through the chamber. The flow through the valve can take place correspondingly asymmetrically (not centrically, i.e. asymmetrically with respect to a central axis). For example, different flow rates may exist on different (e.g., opposite) valve sides.

In one embodiment, the drive unit, in particular the respective drive components, and at least the first (or also the second, the third or more) valve disk can be designed and coupled in such a way that at least the first of the valve disks can be adjusted along a first adjustment axis and the first adjustment axis runs transversely relative to the first opening axis. It goes without saying that the number of valve disks preferably corresponds to the number of valve seats, i.e. that a valve can have several (more than three) valve seats and a corresponding number of valve disks.

According to one embodiment, the main process chamber can enclose a main internal volume and the secondary process chamber can enclose a secondary internal volume, with the main internal volume being larger than the secondary internal volume.

In one embodiment, the vacuum processing system can have an electrostatic holding device, in particular a chuck, arranged in the main process chamber.

In particular, the vacuum control valve can have at least the first valve seat and at least two further valve seats, and the valve seats can define a first valve opening and at least two further valve openings. The valve seats may be arranged symmetrically about the electrostatic chuck.

In one embodiment, the valve seats and/or the valve openings can be in the form of ring segments and arranged in such a way that the respective inner circular arcs or outer circular arcs of the ring-segment-shaped valve seats or valve openings lie on a common circle.

The chuck can, for example, be round and/or define a circular surface as a holding surface for a substrate. Due to the overall ring-shaped arrangement of the valve opening around the chuck, a correspondingly optimized fluid flow behavior around and over the chuck can be implemented.

In one embodiment, the first and second valve part openings, in particular the third valve part opening, can be arranged symmetrically around a central axis of the vacuum control valve, the central axis extending through a valve center point, in particular forming a central axis of the flow channel. Due to its geometry, the valve can on the one hand define a flow path for a fluid and thus on the other hand a limited flow channel for the fluid. The central axis lies in particular in the center of this channel and extends in accordance with the extension of the channel. A center point of the chuck bearing surface lies in particular on the central axis.

With a valve according to the invention, the above-mentioned flows can be advantageously regulated, i.e. even at very low pressures and while providing and maintaining an essentially symmetrical and laminar flow.

The vacuum control valve can in particular have a control unit, in particular a regulation unit, wherein the drive unit (and its drive components) can be controlled using a control signal provided by the control unit, in particular using a controlled variable.

In particular, each drive component of the drive unit can be controlled individually by means of an (individual) control signal.

In one embodiment, the control unit can have a flow functionality configured in such a way that when it is executed, at least one of the valve disks coupled to the drive unit is adjusted to a specific intermediate position between the open position and the closed position.

In particular, the at least one coupled valve disk can be adjusted linearly along an adjustment axis and a distance between its contact surface and the corresponding sealing surface can be smaller in the intermediate position than in the open position and larger than in the closed position

According to one embodiment, the vacuum control valve can have at least the first and the second valve seat, the first and the second valve disk, and the first drive component, which is coupled to the first valve disk, and the second drive component, which is coupled to the second valve disk. The flow functionality can be configured in such a way that the valve disks can be positioned individually between the respective open position and the respective closed position as a function of flow information.

Such a targeted relative and individual open position between the valve seat and the valve closure and the opening range of the valve opening that can be adjusted as a result enables the advantageous pressure and flow regulation. Such controls can typically be used, for example, when using process gas and the associated need to set a target pressure. A continuous laminar flow of the medium through the openings and in particular through the main process chamber that can be effected in this way can avoid pressure fluctuations and a setpoint pressure can be reached more quickly.

In particular, the individual disk positions (intermediate positions) can be controlled (by means of the control signal) each individually or continuously and thus a particularly continuous regulation of the volume or mass flow of a medium through the valve opening can be provided. The flow can be maintained in a laminar manner in particular. Such a regulation is provided in particular by a stepper motor or a servomotor of the drive unit.

• • einen Massen- oder Volumenstrom des Fluids durch die Hauptprozesskammer und/oder die Nebenprozesskammer,
• • eine Strömungsgeschwindigkeit des Fluids in der Hauptprozesskammer und/oder Nebenprozesskammer,
• • eine Strömungsgeschwindigkeitsverteilung bezüglich eines Innenvolumenquerschnitts für die Hauptprozesskammer und/oder die Nebenprozesskammer,
• • einen Druckunterschied zwischen der Hauptprozesskammer und der Nebenprozesskammer,
• • einen Fluidzufluss in die Hauptprozesskammer,
• • einen Fluidabfluss aus der Nebenprozesskammer.

The flow information can in particular have or provide at least one of the following information:

• • a mass or volumetric flow of the fluid through the main process chamber and/or the secondary process chamber,
• • a flow rate of the fluid in the main process chamber and/or ancillary process chamber,
• • a flow velocity distribution with respect to an internal volume cross-section for the main process chamber and/or the auxiliary process chamber,
• • a pressure difference between the main process chamber and the secondary process chamber,
• • a fluid inflow into the main process chamber,
• • a fluid drain from the ancillary process chamber.

The individual valve disks can be positioned individually by means of the control unit in such a way that a symmetrical fluid flow through the main process chamber can be provided as a function of the flow information. This can be achieved, for example, in the case of unequal fluid distribution in one of the process chambers or in the case of spatially unequal fluid flow into the main process chamber by setting and/or dynamically adapting different opening cross-sections for the individual valve part openings. This can also be achieved, for example, by setting the same opening cross sections for the valve part openings if the fluid distribution or the fluid inflow is homogeneous.

In one embodiment, the positioning of the valve disks can be individually dynamically adjustable and thus continuous regulation of the fluid flow through the main process chamber can be provided. If the fluid distribution in the process chamber changes, e.g. if a new or different process gas is added, the valve disk positions can be adjusted during or before a machining process.

In one embodiment, a defined flow behavior through the vacuum control valve, in particular through the at least two partial valve openings, can be set and/or regulated, in particular with the flow behavior through the vacuum control valve being adjustable asymmetrically with respect to a central axis of the vacuum control valve and the central axis extending through a valve center point.

In one embodiment, when there is an inhomogeneous fluid flow through the main process chamber and by performing the flow functionality, a symmetrical fluid flow can be set.

The vacuum processing system has in particular at least one sensor unit designed in such a way that the flow information can be detected by means of the sensor unit, in particular a pressure sensor or a sensor for chemical analysis of a gas composition.

In one embodiment, the flow path can connect the main process chamber and the secondary process chamber, with the main process chamber being able to be separated from the secondary process chamber in a gas-tight manner by the vacuum control valve, ie the flow path being closable.

According to one embodiment, the first valve seat and the second valve seat can be arranged in a common plane. Alternatively, the first valve seat and the second valve seat can be arranged obliquely relative to one another in such a way that the plane defined by the first sealing surface and the plane defined by the second sealing surface enclose a defined angle. The valve seats can, for example, be aligned in such a way that the defined sealing planes each include a side surface of a virtual pyramid.

In one embodiment, the alignment can be such that the opening axes defined by the respective valve opening of a valve seat intersect, in particular intersect at a common intersection. The common point of intersection lies in particular on the central axis of the valve.

According to one embodiment, the drive unit has at least one motor and at least one guide component, in particular a valve or guide rod, that can be moved along an adjustment axis under the control of the at least one motor, the valve disk with the guide component being movable relative to the valve seat.

The position of the adjustment axis is defined in particular by the extent of the guide component, which is designed or designated, for example, as a push rod, valve rod or guide rod, and/or by the linear movement direction provided by the drive unit.

In one embodiment, the vacuum processing system or the vacuum control valve can have a separating device for separating a process atmosphere area from an outside atmosphere area. In particular, this relates to an embodiment of the control valve as a vacuum valve.

The process atmosphere area is to be understood in particular as an area that can be defined by a process chamber (vacuum chamber). A process atmosphere, in particular a vacuum, can be created in this area for processing substrates. Components intended for this area must meet increased requirements, e.g. in terms of material durability and atmospheric purity (particle generation). Accordingly, the external atmosphere area can be understood in particular as an area which surrounds the process chamber and in which, for example, normal atmospheric conditions are present, for example room air.

The drive unit can be assigned at least partially, in particular completely, to the outside atmosphere area and the valve seat and valve closure in particular to the process atmosphere area.

The separating device can be formed by a bellows, for example. For example, the bellows can be provided within the valve housing or the drive unit.

For example, the vacuum control valve of the vacuum processing system, in particular the drive unit, can have a drive housing in which the valve rod for moving the valve disk is movably mounted. The valve rod projects on the one hand from the drive housing into the secondary process chamber (process atmosphere area) and on the other hand is coupled to a motor, e.g. by means of a gear. A separating device (e.g. a dynamic bellows) can be provided here, the first end of which is connected in a gas-tight manner to the housing (or another static element in the drive housing) and the second end of which is connected to the valve rod in a gas-tight manner. This achieves an atmospheric separation of the location of the bearing of the valve rod (outer atmosphere area), at which particles could be generated by the relative movements that occur and where lubricants may be used, from the process atmosphere area, which is critical in terms of atmospheric purity, while at the same time providing the controlled mobility of one or more valve plate.

A housing is made of aluminum or stainless steel, for example, or is internally coated with aluminum or another suitable material, while the valve disk and the bellows can be made of steel. Alternatively or additionally, the bellows can have a nickel-based alloy or be made of a nickel-based alloy be. The bellows, which can be expanded and compressed in its longitudinal axis within the area of the adjustment path of the plate, thus seals the process atmosphere area from the outside atmosphere area in an airtight manner. Two types of bellows are mainly used. On the one hand a diaphragm bellows, on the other hand a corrugated bellows, the latter being distinguished from the diaphragm bellows in that it has no weld seams and can be cleaned more easily, but has a lower maximum stroke.

• 1 eine erste Ausführungsform eines erfindungsgemässen Vakuumbearbeitungssystems;
• 2 eine Ausführungsform eines Vakuumventils eines erfindungsgemässen Vakuumbearbeitungssystems; und
• 3 eine Ausführungsform eines Vakuumventils eines erfindungsgemässen Vakuumbearbeitungssystems.

The device according to the invention is described in more detail below purely by way of example on the basis of concrete exemplary embodiments illustrated schematically in the drawings, with further advantages of the invention also being discussed. Show in detail:

• 1 a first embodiment of a vacuum processing system according to the invention;
• 2 an embodiment of a vacuum valve of a vacuum processing system according to the invention; and
• 3 an embodiment of a vacuum valve of a vacuum processing system according to the invention.

1 shows a first embodiment of a vacuum processing system 1 with a vacuum chamber 10 (process chamber) and a vacuum control valve 20 in a lateral sectional view. The vacuum control valve 20 is designed to regulate a volume or mass flow of a fluid flowing through the vacuum chamber 10 and to interrupt a flow path of the fluid in a gas-tight manner. For this purpose, the vacuum control valve 20 has a valve seat 21a which defines a valve opening 22a with an opening axis O. The valve 20 also has a valve plate 23a. The valve seat 21a provides a sealing surface on its underside, with the valve disk 23a having a contact surface (sealing surface on the disk side) which is designed to come into contact with the (seat-side) sealing surface and thereby enables the valve 20 to be closed in a gas-tight manner. The contact is realized in particular indirectly by a seal provided between the sealing surface on the seat side and the plate side. Even if the structural elements valve seat and valve disk are not directly (ie only indirectly through the intervening seal) physically in contact, this state should be understood as an in-contact state.

The valve disc 23a can be moved from an open position (shown in Fig 1 ) in a closed position (not shown) displaceable. In the closed position, there is therefore a sealing contact between the sealing surface and the contact surface via an intermediate sealing element. The valve opening 22a is closed in a gas-tight manner.

The sealing element can be a polymer-containing seal, which is arranged on the underside of the valve seat 21a by means of clamping, gluing or vulcanization. The seal can be designed as an O-ring, for example. Alternatively, the sealing element can be arranged on the valve disk 23a.

The drive unit 30 can, for example, be an electrically operated actuator or motor (e.g. linear motor or stepper motor) with a linear adjustment axis V. The drive unit 30 can provide a stroke of at least 50 mm, in particular 100 mm

The valve seat 21a is arranged inside the vacuum chamber 10 . The vacuum chamber 10 is divided into a main process chamber 11 for processing a substrate and into a secondary process chamber 12 by the valve seat 21a and thus by the location at which a gas-tight seal can take place (sealing line).

A lower opening 19 of the secondary process chamber 12 connects the vacuum chamber 10 to a downstream vacuum generator, in particular a vacuum pump, for generating the vacuum in the chamber 10. A vacuum valve and/or a pressure sensor can also be provided as a further downstream component.

The vacuum valve 20 is installed in the chamber 10 in such a way that the first sealing surface of the valve seat 21a extends orthogonally to the opening axis O and points parallel to the first opening axis O in the direction of the auxiliary process chamber 12 . The valve plate 23a is correspondingly arranged in the secondary process chamber 12 so that it can be adjusted.

In the embodiment shown, the valve disk 23a is mounted on a guide element 24a. The bearing is designed in particular in such a way that the valve disk 23a can be (slightly) tilted relative to the guide element 24a. The drive unit 30 is coupled to the guide element 24a by means of a valve rod 31 , with which the valve disk 23a can be adjusted by means of the drive unit 30 .

In another embodiment, the valve disk 23a can be coupled directly to the valve rod 31 . The valve disk 23a can be tilted within narrow limits relative to the valve rod, so that the contact surface can be brought into complete contact with the sealing surface. Such tilting can, in particular with an oblique arrangement of the adjustment axis V relative to the opening axis O, reliably close the opening provide voltage 22a. An inclined arrangement as shown makes particularly advantageous use of space possible such that the adjustment device (eg valve rod) requires comparatively little space in the vacuum chamber 10 and the drive unit 30 can be arranged in an advantageous manner with respect to peripheral vacuum elements. In this case, possible downstream elements can be connected to the secondary process chamber 12 without any problems, ie without a spatial restriction caused by the drive unit 30 .

It goes without saying that the valve disk can alternatively be rigidly connected to the valve rod. Here, too, the plate can be connected to the rod in such a way that the adjustment axis V encloses an angle of between 0° and 90° with a plane defined by the seat-side sealing surface, ie is arranged transversely thereto.

The drive unit 30 can also have a bellows for the atmospheric separation of the inner volume of the process chamber 10 (process atmosphere area) from an outer atmosphere (outer atmosphere area). For this purpose, the bellows can be connected to the valve rod 31 on the one hand and, for example, to the inner drive housing on the other hand. In this way, an atmospheric separation of the moving part of the drive unit from the inner volume of the process chamber 10 can be provided. A particle entry, e.g. caused by abrasion, can be prevented in this way. When the valve is open, the bellows is compressed; when the valve 20 is closed, it is expanded or unfolded.

The embodiment according to the invention offers the advantage that the volume of the main process chamber 11 in which the effective processing of the substrate takes place can be kept comparatively small and thus a desired internal pressure in the main process chamber 11 for a specific processing process can be adjusted comparatively quickly.

The secondary process chamber 12 provides an internal volume that is larger than the internal volume of the main process chamber 11 and in which an internal pressure can be regulated by suction through the opening 19, which corresponds to a target processing pressure or is smaller. The secondary process chamber 12 can thus serve as a reserve volume for the main process chamber 11 and provide a rapid adjustment of a process pressure in the main process chamber 11 .

2 shows the vacuum control valve of the vacuum processing system according to 1 in a top view. The valve has a total of three valve seats 21a-c, which are arranged in a ring. Each valve seat 21a-c provides a respective valve opening 22a-c. In the exemplary embodiment shown, the valve openings 22a-c are provided with lattice-like structures which enable a homogeneous flow of fluid through the respective opening. In alternative embodiments, the valve openings 22a-c may be formed without the structure shown or with an alternative fluid-permeable structure.

Each valve seat 21a-c is on its underside (cf. 3 , not shown here) is assigned a respective valve closure 23a-c, as is the case, for example, for the valve seat 21a and the valve closure designed as a valve disk 23a in FIG 1 is shown. The individual valve closures are each coupled to an individually controllable drive unit (a corresponding number of drive components is provided corresponding to the number of valve disks).

As a result, an individual opening cross section and thus an individual flow can be set for each valve opening 22a-c. A mass or volume flow of a fluid can therefore be set individually for each valve opening and independently of the remaining openings. Due to this individual adjustability, a symmetrical fluid flow can be provided through the main process chamber 11 in particular. For this purpose, for example, different offsets can be set for the individual valve openings and thus compensation for inhomogeneous pressure and flow distributions can be achieved.

By providing a process fluid flow that is as symmetrical and homogeneous as possible through the process chamber, the processing of a substrate can be carried out with corresponding accuracy and precision. With a symmetrical flow, it can be ensured, for example, that there is a comparable or the same process gas concentration over the (entire) substrate surface and that, for example, deposition or etching (e.g. ALD or ALE process) takes place homogeneously along the surface.

The valve seats 21a-c of the vacuum control valve are arranged symmetrically around an electrostatic chuck 15 (chuck). The substrate to be processed can be placed on the holding device 15 and held accordingly by means of electrostatic charge. In other words, the chuck 15 is designed to receive a substrate and to hold it at least during a machining process.

This concentric arrangement of the chuck 15 and the valve seats 21a-c allows a symmetry or homogeneity of the fluid flow to be achieved in an optimized manner. The flow around the chuck 15 can thus be largely homogeneous, with the flow rates through the individual openings 22a-c being individually adjustable at the same time. As a result, a correspondingly high degree of homogeneity with regard to the substrate processing can be provided.

In addition, the arrangement of the valve close to the chuck 15 and around the chuck 15 creates an advantageous limitation of a particle flow or the particle flow conductance in the area of the chuck 15 (in particular in the closed position). As a result, the sealing line of the valve is comparatively close to the chuck 15, ie close to the location of the substrate processing. This leads directly to improved (homogeneous) substrate processing.

For example, by gradually approaching a valve disk to the associated valve seat 21a-c, the opening cross section of the relevant valve part opening can be reduced step by step, in particular continuously.

The vacuum control valve 20 thus also makes it possible to adjust a fluid flow through the valve opening(s) in a targeted manner. If a specific internal pressure is to be provided in the main process chamber, a specific quantity (mass or volume) of fluid that flows out per unit of time can be set by means of the vacuum control valve 20 . An internal pressure in the main chamber 11 determined by means of a pressure sensor, for example, can be used as a controlled variable. Alternatively, the opening cross section can be set and varied in a controlled manner using a predetermined rule.

It should be noted that the invention is not limited solely to embodiments with three valve part openings, valve seats and valve disks, but in particular also extends to solutions that each have two or more than three valve openings, valve seats and valve disks.

The division of the total valve opening into a plurality of partial openings 22a-c also offers the advantage that a plurality of valve closures 23a-c is also provided and the mass of each individual closure can thus be reduced individually. Due to the lower individual masses to be moved, significantly shorter adjustment times can be achieved, i.e. the time required to move one or all of the valve closures from an open position to a closed position (or vice versa) can be reduced.

In addition, the probability of the valve snapping shut can be reduced when the valve opening is very small, since the forces applied to the individual valve disks are each significantly smaller than the force would be with a connected valve disk of the same area, and correspondingly counteracting holding forces can be implemented more easily in terms of design are.

An initially asymmetrical fluid flow through the chamber 11 can be compensated for by means of the vacuum control valve 20 according to the invention. By providing different opening states of the individual valve part openings 22a-c, which are also dynamically adaptable, an asymmetry with regard to the gas flow can be compensated. For this purpose, the valve closures 23a-c can be placed in different positions (distances from the respective valve seats), as a result of which different opening cross sections are provided in each case. The fluid then no longer flows out centrally through the valve, but also asymmetrically within the valve with respect to the central axis.

The fluid flow can be adjusted to different extents over the course of a chamber cross section by means of different opening states. In other words, the flow behavior of a gas can be set to be different in different areas of the chamber, e.g. different flow speeds can be set on opposite chamber walls.

With such a variable setting of the fluid flow through the valve 20, an inhomogeneous, unequal flow behavior - e.g. caused by a non-central inflow of a process gas - can be compensated in such a way that a resulting flow around the chuck 15 is symmetrical (homogeneous).

3 shows a perspective view of an embodiment of a valve seat 21 together with a corresponding valve disk 23 of a vacuum processing system according to the invention.

The valve seat 21 is embodied by a plate having the shape of a ring segment. The valve seat 21 defines a valve opening 22 through which a fluid (e.g. process gas or precursor) can flow. The valve opening 22 is surrounded by a sealing surface with a sealing element 25 . The sealing element 25 (and the sealing surface) is arranged on the underside of the valve seat 21, i.e. on the side which faces away from the main process chamber 11 in the installed and intended state.

The valve seat 21 also has a structure on the upper side opposite the underside, through which a process fluid is permeable and can flow. The structure can be designed, for example, as a lattice, as a perforated film, in a lamellar form, etc. The structure provides increased stability of the valve seat 21 and homogenization of the fluid flow, ie a flow can be divided into individual partial flows by means of a plurality of passage channels provided by means of the structure and improved laminar flow behavior can thereby be achieved.

Alternatively, the valve seat 21 can be made without the structure.

The plate-like design of the valve seat 21 enables simple and quick assembly or replacement of the seat 21 in a vacuum processing device, such as in 1 shown, possible. The valve seat plate 21 can be inserted and fixed in the process chamber (main process chamber 11) from above and can also be removed from above without the need for complex dismantling of the rest of the valve or the chamber. The valve seat plate 21 can be supplied or removed, for example, through a transfer opening of the process chamber (not shown), through which the substrate to be processed can be introduced into and/or removed from the chamber.

The valve disk 23 corresponds in shape and spatial extent to the valve seat 21, in particular to the seal 25. By pressing the disk 23 from below against the seal 25, the opening 22 can be closed gas-tight. On its upper side (not visible), the valve disk 23 has a contact surface which corresponds to the shape and spatial extent of the seal 25 or the sealing surface carrying the seal 25 . The contact surface is brought into contact with the seal 25 when the valve is closed.

The underside of the valve disk 23 also has a coupling element 26 for coupling the drive unit to the disk 23 .

Like the valve seat, the valve disk 23 can be mounted from above in a vacuum processing system according to the invention, in particular in the secondary process chamber 12 . For this purpose, the plate 23 can, for example, also be fed in or removed through a transfer opening of the process chamber (not shown), through which the substrate to be processed can be introduced into and/or removed from the chamber.

The comparatively simple feasibility of dismantling and/or assembling both the valve seat 21 and the valve disk 23 is particularly advantageous with regard to predictive maintenance (predictive/preventive maintenance) or possible repair work. For example, the sealing elements arranged on the side of the valve seats 21a-c are exposed to material stress with each adjustment into or out of the closed position and must therefore be replaced or renewed in regular cycles. Due to the advantageous modular design, a significant time saving can be realized for this maintenance activity compared to conventional valve solutions.

It goes without saying that the figures shown only show possible exemplary embodiments schematically. According to the invention, the various approaches can also be combined with one another and with methods and devices for controlling a volume flow or pressure in a process volume under vacuum conditions of the prior art.

QUOTES INCLUDED IN DESCRIPTION

This list of the documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• US 6629682 B2 [0008]
• US 6994311 B2 [0016]

Claims (23)

Vacuum processing system (1) having • a vacuum chamber (10), which defines an evacuable internal volume for generating a vacuum and for processing a substrate in the internal volume, and • a vacuum control valve (20) for controlling a volume or mass flow through the vacuum chamber (10 ) flowing fluids and for gas-tight interruption of a flow path of the fluid, with □ a first valve seat (21,21a), which defines a first opening axis (O) and a first sealing surface surrounding the first valve opening (O). and □ a first valve disk (23,23a) with a first contact surface corresponding to the first sealing surface, and • a drive unit (30) which is designed and coupled to the first valve disk (23,23a) in such a way that the latter at least from □ an open position in which the first valve disk (23,23a) and the first valve seat (21,21a) are present without contact relative to each other, in □ e closed position, in which there is a sealing contact between the first sealing surface and the first contact surface via an intervening sealing element (25) and the first valve opening (22, 22a) is thereby closed in a gas-tight manner and can be adjusted back, characterized in that • the first valve seat (21, 21a) is arranged within the vacuum chamber (10) and the vacuum chamber (10) is divided into a main process chamber (11) for processing the substrate and a secondary process chamber (12), • the first sealing surface is orthogonal to the first opening axis (O ) extends and points in the direction of the secondary process chamber (12) and • the first valve disk (23, 23a) is adjustably arranged in the secondary process chamber (12). Vacuum processing system (1) according to claim 1 , characterized in that the vacuum control valve (20) has • a second valve seat (21b) which has a second valve opening (22b) defining a second opening axis and a second sealing surface surrounding the second valve opening (22b), and • a second valve disk (23b ) with a second contact surface corresponding to the second sealing surface, wherein • the second valve seat (21b) is arranged inside the vacuum chamber (10) and together with the first valve seat (21, 21a) the vacuum chamber into the main process chamber (11) and the secondary process chamber ( 12), • the second sealing surface extends orthogonally to the second opening axis and points in the direction of the secondary process chamber (12) and • the second valve disk (23b) is arranged adjustably in the secondary process chamber (12), with an overall valve opening of the vacuum control valve being at least controlled by the first Valve opening (22a) as the first partial valve opening and the second valve opening (22b) as the second valve partial opening is formed. Vacuum processing system (1) according to claim 1 or 2 , characterized in that the vacuum control valve (10) has • a third valve seat (21c) which has a third valve opening (22c) defining a third opening axis and a third sealing surface surrounding the third valve opening (22c), and • a third valve disk (23c ) with a third contact surface corresponding to the third sealing surface, wherein • the third valve seat (23c) is arranged inside the vacuum chamber (10) and together with the first and second valve seats (21a, 21b) the vacuum chamber (10) into the main process chamber (11 ) and the secondary process chamber (12), • the third sealing surface extends orthogonally to the third opening axis and points in the direction of the secondary process chamber (12) and • the third valve disk (23c) is arranged adjustably in the secondary process chamber (12), with the total valve opening additionally is formed by the third valve opening (22c) as a third partial valve opening. Vacuum processing system (1) according to claim 2 or 3 , characterized in that the drive unit (30) is coupled to the second or third valve disk (23b, 23c) in such a way that the coupled valve disks (23a-c) at least from • a respective open position in which the respective valve disk and the respective valve seat relative to each other without contact, in • a closed position in which there is an axially sealing contact between the respective sealing surface and the respective contact surface via an intermediate sealing element and the respective valve part opening is thereby closed gas-tight, and can be adjusted back. Vacuum processing system (1) according to one of the preceding claims, characterized in that the vacuum control valve (20) has a coupling arrangement, which coupling arrangement mechanically couples the first valve disk (23, 23a) to the second valve disk (23b), and in particular to the third valve disk (23c) and is connected to the drive unit (30) in such a way that the respective valve disks (23, 23a-c) can be adjusted together by means of the drive unit (30). Vacuum processing system (1) according to one of the preceding claims, characterized in that • the drive unit (30) has at least a first and a second, in particular a third, drive component, in particular respective motors, and • the first drive component with the first valve plate (23a) and the second drive component is coupled to the second valve disk (23b), in particular the third drive component is coupled to the third valve disk. Vacuum processing system (1) according to one of the preceding claims, characterized in that the drive unit (30) and at least the first valve disk (23, 23a) are designed and coupled in such a way that • at least the first (23, 23a) of the valve disk along a first Adjustment axis (V) is adjustable and • the first adjustment axis (V) runs transversely relative to the first opening axis (O). Vacuum processing system (1) according to one of the preceding claims, characterized in that the main process chamber (11) encloses a main internal volume and the secondary process chamber (12) encloses a secondary internal volume, the main internal volume being larger than the secondary internal volume. Vacuum processing system (1) according to one of the preceding claims, characterized in that the vacuum processing system (1) has an electrostatic holding device (15), in particular a chuck, arranged in the main process chamber (11). Vacuum processing system (1) according to claim 9 , characterized in that • the vacuum control valve (20) has at least the first valve seat (21,21a) and at least two further valve seats (21b-c) and the valve seats (21,21a-c) have a first valve opening (22,22a) and define at least two further valve openings (22b-c) and • the valve seats (21,21a-c) are arranged symmetrically around the electrostatic holding device (15). Vacuum processing system (1) according to claim 10 , characterized in that the valve seats (21, 21a-c) and/or the valve openings (22, 22a-c) are designed in the form of ring segments and are arranged in such a way that the respective inner circular arcs or outer circular arcs of the ring-segment-shaped valve seats or valve openings lie on a common circle . Vacuum processing system (1) according to one of the preceding claims, characterized in that the vacuum processing system (1) has a control unit, in particular a regulating unit, and the drive unit can be controlled using a control signal provided by the control unit, in particular using a controlled variable. Vacuum processing system (1) according to claim 12 , characterized in that each drive component of the drive unit can be controlled individually by means of the control signal. Vacuum processing system (1) according to claim 12 or 13 , characterized in that the control unit has a flow functionality configured in such a way that when it is executed at least one of the valve disks (21, 21a-c) coupled to the drive unit (30) is moved into an intermediate position between the open position and the closed position. Vacuum processing system (1) according to Claim 14 , characterized in that the at least one coupled valve disk (21, 21a-c) is linearly adjustable along an adjustment axis (V) and a distance between its contact surface and the corresponding sealing surface is smaller in the intermediate position than in the open position and larger than in the closed position is. Vacuum processing system (1) according to Claim 14 or 15 , characterized in that • the vacuum control valve (20) has at least □ the first and the second valve seat (21,21a-c), □ the first and the second valve plate (23,23a-c), □ the first drive component with is coupled to the first valve disk and the second drive component, which is coupled to the second valve disk, and • the flow functionality is configured such that the valve disks (23, 23a-c) depending on flow information individually between the respective open position and the respective closed position are positionable. Vacuum processing system (1) according to Claim 16 , characterized in that the flow information has at least one of the following information: • a mass or volumetric flow of the fluid through the main process chamber and/or the secondary process chamber, • a flow velocity of the fluid in the main process chamber and/or secondary process chamber, • a flow velocity distribution with respect to an internal volume cross-section for the main process chamber and/or the ancillary process chamber, • a pressure difference between the main process chamber and the ancillary process chamber, • a fluid inflow into the main process chamber, • a fluid outflow from the ancillary process chamber. Vacuum processing system (1) according to Claim 16 or 17 , characterized in that the valve plates (23, 23a-c) can be positioned in such a way that a symmetrical fluid flow through the main process chamber (11) can be provided as a function of the flow information. Vacuum processing system (1) according to one of Claims 16 until 18 , characterized in that the positioning of the valve disks (23, 23a-c) can be individually and dynamically adjusted and thus continuous regulation of the fluid flow through the main process chamber (11) can be provided. Vacuum processing system (1) according to one of Claims 16 until 19 , characterized in that a defined flow behavior through the vacuum control valve (20), in particular through at least two partial valve openings (22a-c), can be set and/or regulated, in particular the flow behavior through the vacuum control valve being adjustable asymmetrically with respect to a central axis of the vacuum control valve (20). and the central axis extends through a valve center. Vacuum processing system (1) according to one of Claims 16 until 20 , characterized in that when there is an inhomogeneous fluid flow through the main process chamber (11) and by executing the flow functionality, a symmetrical fluid flow can be set. Vacuum processing system (1) according to one of Claims 16 until 21 , characterized in that the vacuum processing system (1) has at least one sensor unit designed in such a way that the flow information can be detected by means of the sensor unit. Vacuum processing system (1) according to one of the preceding claims, characterized in that the flow path connects the main process chamber (11) and the secondary process chamber (12) and the main process chamber (11) can be separated from the secondary process chamber (12) in a gas-tight manner by the vacuum control valve (20).

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